This is the 11819th most frequent Polish word.
koszykówka
Basketball.
The word 'koszykówka' in this sentence refers to the sport of basketball, used as an object of the verb 'grać' (to play), indicating the activity the subject enjoys.
Lubię grać w koszykówkę.
I like playing basketball.
Here, 'koszykówka' functions as the subject of the sentence, indicating the sport itself and its increasing popularity.
Koszykówka jest coraz bardziej popularna w Polsce.
Basketball is becoming more popular in Poland.
In this sentence, 'koszykówka' is again the object of the verb 'graliśmy' (we played), specifying the sport played during the class.